Artificial hair articles and process for the preparation thereof

ABSTRACT

Artificial hair article made of filamentary shaped strands of a fiber-forming, thermoplastic synthetic polymer containing as uniformly dispersed therein and incorporated therewith, particles of cross-linked copolymer of 0.01 to 2 microns in size which do not decompose at the melting point of the fiber-forming, thermoplastic synthetic polymer, in an amount of 0.1 to 10 percent by weight, the strands having a uniformly distributed fine slit-like grooved pattern along their entire length.

United States Patent 1191 Kimura et al.

[ 1 Jan. 22, 1974 ARTIFICIAL HAIR ARTICLES AND PROCESS FOR THE PREPARATION THEREOF [75] inventors: Nobuo Kimura, Yokkaichi; Yukio Mizutani, Tokuyama, both of Japan [731 Assignees: Tokuyama Soda Kabushiki Kaisha,

Yamaguchi-ken; Toa Boshoku Kabushiki Kaisha, Osaka, Japan [22] Filed: Apr. 3, 1972 [21] Appl. No.: 240,796

Related US. Application Data [63] Continuation-in-part of Ser. No. 864,479, Oct. 7,

i969, abandoned.

[30] Foreign Application Priority Data Oct. ll, 1968 Japan 43-74414 521 u.s.c|. 132/53, 200/836 5| Int. Cl ..A4lg3/00 [58] Field of Search ..132/53;260/836 [56] References Cited UNITED STATES PATENTS 3,423,48l l/l969 Mitzutani 260/836 3,301,909 l/l967 Cenci 260/836 OTHER PUBLICATIONS Minoru Kubota et al. Kogyo Kagaku Zasshi, 66 (5) 725-729 (1963) as cited in Chemical Abstracts Vol. 60, p. 6972 C (1964).

Primary Examiner-Louis G. Mancene Assistant Examiner-Gregory E. McNeill Attorney, Agent, or Firm-Leonard W. Sherman et al.

[5 7 ABSTRACT Artificial hair article made of filamentary shaped strands of a fiber-forming, thermoplastic synthetic polymer containing as uniformly dispersed therein and incorporated therewith, particles of cross-linked c0- polymer of 0.01 to 2 microns in size which do not decompose at the melting point of the fiber-forming, thermoplastic synthetic polymer, in an amount of 0.1 to 10 percent by weight, the strands having a uniformly distributed fine slit-like grooved pattern along their entire length.

10 Claims, 4 Drawing Figures ARTIFICIAL HAIR ARTICLES AND PROCESS FOR THE PREPARATION THEREOF This application is a continuation-in-part of copending application Ser. No. 864,479 now abandoned filed Oct. 7, 1969.

This invention relates to artificial hair strands closely resembling natural hair in appearance and hand including luster, microscopic surface texture, etc., as well as to artificial hair articles such as falls, hair pieces, (wiglettes) or wigs made of such hair strands.

More particularly, the invention relates to artificial hair articles composed of filamentary shaped strands of a fiber-forming thermoplastic synthetic polymer in which 0.1 to l percent by weight of particles of 0.01 2p in size of a cross-linked copolymer, which shows no decomposition at the melting point of the fiberforming, thermoplastic synthetic polymer are uniformly dispersed and incorporated and the strands have a uniformly distributed fine slit-like grooved pattern along their entire length.

The filamentary shaped strands obtained by meltspinning a fiber-forming, thermoplastic synthetic polymer have strong surface luster and a waxy hand. Therefore, when they are used as a substitute for hair, their luster and waxy feeling provide a markedly different handling from that of natural hair. Various proposals have been made to overcome this serious objection, such proposals being divided roughly into two categories. One of these includes the attempts to mix inorganic materials, such as titanium dioxide, silicon dioxide, etc., and optionally, pigments, with the fiberforming polymer, followed by melt-spinning of the mixture. The other includes attempts to coarsen the surfaces of melt-spun, filamentary material with a solvent or by surface treatment thereof with an acid or alkali.

However, the first such method reduces the transparency of the filamentary material, consequently increasing the whiteness thereof. Therefore, a greater amount of coloring matter must be used for coloring the filamentary article. Furthermore, none of the attempts has successfully suppressed the metallic luster of the filamentary material, particularly the metallic, reflective luster under sunlight. In the latter proposal an extra step of surface-treating the melt-spun filamentary article is required, complicating the operation. Moreover, yield is not satisfactory and reproducibility of the treating effect is poor, this being industrially quite objectionable. Also, here again sufficient suppression of metallic luster in the product is not accomplished by the surface treatments, and resemblance to natural hair is hardly acquired.

As another proposal, it has recently been proposed to incorporae crystalline cellulose (e.g., Abicell by tradename) prepared by acidhydrolysing or alkali-oxidizing and decomposing cellulose and removing the noncrystalline portion thereof, with the fiber-forming, thermoplastic synthetic polymer, instead of the titanium dioxide, silicon dioxide, etc., and to melt-spin the mixture (Japanese Official Patent Gazette, Publication No. l5585/68).

Because the crystalline cellulose employed in the above proposal has insufficient heat resistance, the resulting aritifical hair article is colored light brown to lightly dark brown, probably due to thermal metamorphosis or decomposition of the cellulose during the melt-spinning, which objectionably affects the coloring of the article to the desired likeness to hair. Furthermore, the process cannot sufficiently reduce the metallic, reflective luster and waxy hand, since increase in the amount of additive to sufficiently suppress them enhances the tendency for undesirable coloring and bubble formation due to decomposition of the cellulose. Accordingly, neither the operation not the products quality as artifical hair are satisfactory. Furthermore, the strength of the filamentary material is unduly impaired, and the product serves no practical purpose.

Research has been conducted for the purpose of overcoming the defects inherent in the conventional proposals as described above, and providing artificial hair articles having the appearance and hand closely resembling those of natural hair, and it has been discovcred that the foregoing drawbacks can be overcome by uniformly dispersing and incorporating a specific amount of a synthetic high molecular material containing cross-linkages, particularly particles of cross-linked copolymer of 0.01 2 microns in size, which does not decompose at the melting point of the fiber-forming, thermoplastic synthetic polymer, in and with the fiberforming polymer, whereby artificial hair strands and final articles having the appearance and handling of natural hair can be provided.

Upon examining the surface structure of the artificial hair prepared as above, it is found that the structure closely resembles that of the natural hair to such a degree as has never been achieved before, as persuasively demonstrated by the attached figures.

Accordingly, an object of the present invention is to provide artificial hair strands and articles from which the defects inherent in the past proposals are eliminated, and which have the appearance and handling closely resembling those of natural hair, including such properties as luster and microscopic surface structure.

Another object of the invention is to provide a process whereby the above artificial hair strands and articles can be prepared through very easy means and with high qualitative reproducibility.

Still many other objects and advantages of the present invention will become apparent from the following description.

In the present invention, the term artificial hair article" is used to collectively indicate strands used as hair of, for example, dolls and other toys, mascots, etc; as well as hair pieces, wigs, or falls, artificial furs, etc., for ladies and gentlemens use which are prepared from such strands.

The fiber-forming thermoplastic synthetic polymers useful for the present invention include, for example, polyacrylonitrile, polyvinylidene chloride, poly(vinylidene chloride-vinyl chloride), poly(ethylene-vinyl chloride), poly (ethylene-vinyl acetate), and polymeric blends thereof. Preferred polymers include polyethylene, polypropylene, polyesters such as poly(ethylene glycol terephthalate) and poly(ethylene glycol terephthalate-isophthalate), poly(acrylonitrile-vinyl chloride), polyvinyl chloride, and polymeric blends thereof. Still more preferred polymers include polyamides such as 6-nylon, 6,6-nylon. ll-nylon. 6,l O-nylon.

eta; polyamide-polypropylene blends; polyamidepoly( acrylonitrile-vinyl chloride) blends; and polyamide-polyvinyl chloride blends.

In the present invention, the cross-linked copolymers which do not fuse or decompose at the melting point of the fiber-forming, thermoplastic synthetic polymer, to

be uniformly dispersed in the fiber-forming polymers in the form of particles, include any polymers which contain cross-linkages and do not decompose at the specified melting point, while cross-linked copolymers comprising (a) radical-polymerizable, monoethylenically unsaturated monomer and (b) radical-polymerizable dior triethylenically unsaturated cross-linking agent are preferred.

The radical-polymerizable, monoethylenically unsaturated monomer includes such monomers as, for example, styrene, vinyltoluene, methyl vinyl pyridine, methacrylonitrile, acrylonitrile, methacrylic acid, methacrylic acid alkyl esters, wherein the alkyl group contains one six carbon atoms, e.g., methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, etc., acrylic acid, acrylic acid alkyl esters wherein the alkyl group contains one six carbon atoms, e.g., methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, etc., vinyl acetate, and vinyl chloride. Obviously, the above monomers can be used singly or in combination.

Preferred radical-polymerizable dior triethylenically unsaturated cross-linking agents (b) include di-vinylbenzene, divinyltoluene, tri-vinylbenzene and di-vinylsulfone.

According to the present invention, such cross-linked copolymer is used as particles of not greater than 211 in size, normally ranging from 0.01 to Zn, preferably 0.0] to 11.1., inter alia, 0.1 141.. By using the particles of specified size in an amount ranging from 0.1 to percent by weight to the fiber-forming polymer, artificial hair articles closely resembling natural hair, particularly in the surface structure as later explained referring to the attached drawings, can be prepared without clogging the spinning nozzle or filter of the extruder, with no substantial reduction in the strength of meltspun filamentary material, under the spinning condi' tions as later described.

The above quantity of the additive can be suitably vaired according to the thickness of the filamentary shaped article of the fiber-forming, thermoplastic synthetic polymer. For example, when the diameter of the cross-section of the filaments range from 0.08 0.12 mm, use of particles in an amount in the order of 0.5 4 percent by weight is recommended. If the filaments are finer, that is, approximately 0.01 0.04 mm in cross-sectional diameter, it is desirable to use approximately 0.1 2 percent by weight of the particles of the cross-linked copolymer. Again, if still thicker artificial hair is to be prepared, up to 10 wt. of the additive can be used, although such an amount normally will be considered rather excessive.

Use of less than 0.] percent by weight of the additive fails to achieve the effects which make the product resemble natural hair, particularly, sufiicient delustering cannot be accomplished. When more than 10 wt. of the cross-linked copolymer is used, the desirable effects of the present invention are not achieved, and substantially all the luster is lost and the product looks like dead or fallen hair.

The cross-linked copolymer particles employed in the present invention are uniformly dispersed in the filamentary shaped article, and intimately incorporated with the latter. Various factors work for accomplishing such uniform dispersion. For example, the surface structure of the particles and their compatibility or incorporatability with the fiber-forming, thermoplastic synthetic polymer affect the dispersibility. Particularly, the configuration or shape of the particles is a significant factor. For example, spheroidal particles can be easily and uniformly dispersed compared with polygonal particles of uneven grain sizes, such as obtained by grinding blocks of cross-linked copolymer material.

The preferred spheroidal particles can be prepared, for example, by the process normally referred to as suspension polymerization in which the monomer and cross-linking agent are dispersed in water and copolymerized. In such case, a surfactant should be used to facilitate the dispersion of monomer. Consequently the surfaces of the formed polymer shows strong coagulation property due to the use of surfactant. Furthermore, because salting out is performed to recover the polymer which is formed, the polymeric particles form blocks or a mass through secondary coagulation. The polymer produced as above is not a preferred crosslinked copolymer for the product of the present invention, since its uniform dispersion in the thermoplastic synthetic polymer is difficult. The most preferred copolymer particles for the subject product satisfy the two conditions, i.e., that they are spheroidal, and that the surface thereof exhibits no coagulation tendency. One method of making such copolymer particles is to use a combination of monomer or monomers with a solvent which dissolves the monomer or monomers but not the polymer thereof, and to perform the copolymerization in the presence of a cross-linking agent. The spheroidal copolymer particles suited for the purpose of the present invention can be obtained as above, because no surface active agent to assist dispersion of monomer is required, since the monomer and crosslinking agent are dissolved in the solvent. The surfaces of the formed particles are highly compatible with organic matter, but exhibit substantially no coagulating tendency. Furthermore, the particle size is freely controllable by adjusting the amount of cross-linking agent to the monomer, i.e., use of 0.5 30 percent based on the monomer of cross-linking agent is adequate, for making the particles of the size suitable for the present invention.

The polymerization can be performed using a conventional initiator for radical polymerization, for example, benzoyl peroxide, azoisobutyronitrile, etc. Typical cross-linked copolymer particles can be obtained by polymerizing a styrene-divinylbenzene system in nheptane, using benzoyl peroxide. Also, dispersion of the particles in the thermoplastic, synthetic polymer is affected by compatibility of the two. Generally particles of which the monomeric component is entirely or partly styrene exhibit excellent dispersibility. Normally there is also a tendency that the copolymers of the monomer or monomers containing groups of greater negativity show less dispersibility. When polyamidecontaining polymers are used as the thermoplastic synthetic polymer, relatively easily dispersible particles can be formed using as the monoethylenically unsaturated monomer (a), besides styrene, acrylamide or acrylonitrile.

In the present invention, the method of dispersing the cross-linked copolymer particles in the filamentary shaped article is not critical. Normally chips or powder of the fiber-forming, thermoplastic polymer is mixed with the copolymer particles, optionally subjected to a pelletizer, melt spun, and formed into the desired artificial hair article through drawing and/or heat treatment.

Alternatively, first a master batch of thermoplastic synthetic polymer containing the cross-linked copolymer particles at a high content may be prepared, which then is mixed with a suitably additional amount of the thermoplastic, synthetic polymer, to be together meltspun to form strands. This latter process is advantageous in that better dispersion of the particles can be achieved.

As already mentioned, the artificial hair article of the invention is offered in such forms as artificial hair strands, and hair pieces, wigs, falls, etc., made of such hair strands. The as-spun strands formed by melt extrusion as above are stretched, and if necessary, further subjected to post heat-treatment. Conditions of the stretching and heating treatments are variable depending on the type of fiber-forming, thermoplastic synthetic polymer employed. When the polymer is a polyamide or a polymer blend composed chiefly of a polyamide, the stretching may normally be conducted at a temperature ranging from room temperature to 130C. at a stretch ratio of 3 to 7. The post heat treatment is not always necessary, but it is sufficient to conduct the post heattreatment, for instance, at 80 90C. for about minutes. Also when the polymer is a polyolefin such as polyethylene, polypropylene, etc., or a polyolefin blend composed chiefly of such polyolefin or polyolefins, it is normally preferred that the stretching be carried out at a temperature between 80C. and the melting point of the polymer at a stretch ratio of 3 to 10 and that the post heat-treatment be performed for about 10 minutes at a temperature between 80C. and a temperature 20C. lower than the melting point of the polymer.

When the polymer is a polyester such as poly (ethylene glycol terephthlate), poly(ethylene glycol terephthalate-isophthalate), etc., or a polyester blend composed chiefly of such polyester or polyesters, it is normally preferred that the stretching be conducted at a temperature between 100C. and the melting point of the polymer at a stretch ratio of 3 to 10 and that the post heat treatment be carried out at a temperature ranging from 130C. and the temperature 20C. lower than the melting point of the polymer for about 10 minutes.

Furthermore, when the polymer is polyvinyl chloride, poly(ethy1ene-vinyl chloride), poly(ethylenevinyl acetate), poly (vinylidene chloride-vinyl chloride), polyvinylidene chloride, or a polymer blend composed chiefly of one or more of the foregoing, it is normally preferred that the stretching be conducted at a temperature between 60C. and the temperature 10C. lower than the melting point of the polymer at a stretch ratio of 1 to 5. Generally, the post heat-treatment is unnecessary, but it is possible to conduct it at a temperature between 60C. and the temperature 10C. lower than the melting point of the polymer, if necessary.

Still further, when the polymer is polyacrylonitrile, po1y(acrylonitrile-vinyl chloride) or a polymer blend composed chiefly of one of the foregoing, it is normally preferred that the stretching be conducted at a temperature ranging from 110C. to the temperature 20C. lower than the melting point of the polymer at a stretch ratio of 2 to 6, and that the post heat-treatment be carried out at a temperature between 120C. and the temperature 20C. lower than the melting point of the polymer for about 10 minutes.

In the above discussion, the term, "composed chiefly of means that at least percent by weight of the polymer blend is the named polymer or coplymer.

The artificial hair articles of the present invention closely resemble natural hair, much more than conventional articles in the field. They have adequate gloss but are free of objectionable metallic luster or brightness, have a hand almost the same to that of natural hair, and furthermore retain the favorable properties of the synthetic polymer employed, such as high strength, etc. The appearance and handling of the products closely resembling those of natural hair can also be confirmed by microscopic observation.

Turning to the drawings FIG. 1 is a microscopic photograph of hair of an adult female and FIG. 2 is a similar photograph of an artificial hair article of the present invention using polypropylene as the fiber-forming, thermoplastic synthetic polymer, and styrenedivinylbenzene copolymer as the cross-linked copolymer particles (the magnification being the same to that of FIG. 1). FIG. 3 is a similar photograph of the same magnification, of an artificial hair article prepared in the identical manner with that of FIG. 2 except that no cross-linked copolymer particles are incorporated. FIG. 4 is a similar photograph of the same magnification, of the article prepared in an identical manner with that of FIG. 2, except that the cross-linked copolymer particles are replaced by titania particles of the same size. In the graduation forming the backgrounds of the photographs, one scale denotes 10 microns.

As can be clearly observed in FIG. I, a randon, fine slit-like grooved pattern is as a whole uniformly distributed on the surfaces of natural hair, along the direction of its length. Whereas, in the article of FIG. 4, none of such surface structure characteristic to natural hair is observed. The product of FIG. 4 indeed had unnatural metallic gloss and waxy hand. In contrast thereto, the photograph of a product of the present invention in FIG. 2 shows a surface structure extremely close to that of natural hair as shown in FIG. 1. Accordingly, it is to be understood that the strands of the present invention are characterized as having a fine slit-like grooved pattern uniformly distributed along the entire length of the strand. This is a characterization which distinguishes the strands of the present invention from conventional artificial hair strands and a characterization which allows the artificial hair strands of the present invention to very closely resemble natural hair. It can be understood that the conventional product incorporated with titania particles instead of the cross-linked copolymer particles (the particle size, amount of particles, and spinning as well as drawing conditions being identical for the two products) has a surface structure greatly differing from that of the subject product.

The products of this invention formed of the fiberforming, thermoplastic synthetic polymer containing cross-linked copolymer particles dispersed therein possess handling and luster much more alike those of natural hair, compared with the conventional artificial hair formed of thermoplastic, synthetic polymer in which an inorganic material such as titania or silica is dispersed. Particularly in the sunlight, the products of this invention exhibit reflection quite similar to that of natural hair. However, it is impossible to show the degree of resemblance or of difference between conventional artificial hair articles, products of this invention, and natural hair, as to such properties as handling and luster, by means of mechanically measured, numerical data, since judgment of such properties is performed by human senses. Accordingly, in the later given working Examples, evaluation of effects of the invention were entrusted to the judgment of experts.

The artificial hair strand obtained by the invention closely resembles living human hair, and provides an excellent material for wigs, hair pieces, falls, etc., and also for hair of dolls.

Obviously, the artificial hair strands can be mixed with pigment or dyed in accordance with desired hair color, to provide silver, black, brunet, blonde or golden hair. As such colored artificial hair with pigment or dyestuff, black hair colored with carbon black (C.I. No. 77,265), and phthalocyanine blue (C.l. No. 74,160); golden hair colored with cadmium yellow (C.[. N. 77,199), permanent red FSR (C.l. No. 15,865), and carbon black; brown hair colored with benzidine yellow (C.l. No. 21,090), permanent red FSR, phthalocyanine blue, and carbon black; and beige hair colored with cadmium yellow, permanent red FSR, and carbon black; etc. may be named.

The artificial hair strands obtained in accordance with the present invention can be formed into such articles as hair pieces, wigs, falls, etc., as follows:

For instance, a tow of about 100,00 deniers is formed from strands of a dimaeter of about 50 microns. Five or Six of such tows are collected to form a bundle of about 500,000 deniers. The bundle so formed is cut into staples of about inch in length. These staples are wound up around a metal pipe having a suitable diameter and thereon heat set at a temperature about C. lower than the melting point of the resin used for about 30 minutes. The so curledly set staples are loosened and thinly expanded on a cloth tape with ends of the staples being arranged in a line. Then, one end of each of the staples is stiched onto the cloth tape by a sewing machine. Then, the cloth tape with staples being stiched thereon is sewed onto a net. In this way an arti' ficial hair article is prepared.

Into the artificial hair strands of the present invention antioxidants, ultraviolet ray absorbing agents, other stabilizing agents, antistatic agents, dispersing agents, wetting agents, etc., may be added. If desired, concurrent use of titania or silica is also permissible.

The present invention will be hereinafter explained with reference to the working examples, which of course are in no way intended to limit the scope of this invention.

In the following Examples, each type of artificial hair strand was collected into a bundle of approximately 2 cm in diameter, in the form of a pony-tail, and evaluated for luster, handling etc., by plural experts. The best grade (the artificial hair judged to be substantially the same as human hair) is given 5, and that which is very poor in quality and suitable for no practical purpose is graded l, anything therebetween being graded from 4 to 2, by the relative standard of evaluation.

EXAMPLE 1 Three (3) parts of copolymer particles obtained through emulsion polymerization of 5 parts of styrene, 1 part of Z-methyl-S-vinylpyridine and 0.3 part of divinyl-benzene (50 percent purity) in an aqueous medium containing a minor amount of Monogen (tradename of alkyl sulfate produced by Daiichi Kogyo Seiyaku Kabushiki Kaisha) at 80C. for 6 hours, using [98,0 as the initiator, were added to 97 parts of polypropylene. Also 0.] percent, 0.05 percent, and 0.3 percent based on the polypropylene of Cadmium Yellow (C.l. No. 77,199), Permanent Red FSR (C. l. No. 15,865), and Carbon Black (C.l. No. 77,265) were added to the mixture, and pelletized into chips, followed by melt-spinning. The product was beige in color and resembled human hair. The particles of this Example had to be pulverized in a ball mill in order to cope with secondary coagulation. The judgement was 3.

Example 2 The monomers identified in Table 1 and divinylbenzene (10 percent to the monomer) were polymerized in n-heptane at C. for 4 hours with stirring, and formed into particles of 0.1 1pm in diameter. The particles were mixed with the indicated polymer in the amount of 3 percent in each run, and to the mixture pigments identified in the same table were added at the specified ratios to provide black, blonde and golden hair as shown in Table l. The mixtures were each spun into monofilament of 50 deniers in thickness. All the products closely resembled human hair as demonstrated in Table 1, unlike the concurrently given controls.

TABLE 1 Monomeric Run No. compo Polymer nents of particles "4 St:MMS do black do 5 [1:1] 5 StcMMA Polyblack dry hand. 5

11:1) propyno metallic lene luster MVP:AN do black do 4 (1:2) **7 MMAzAN do black do 4 (1:1) 8 VA do black do 4 9 St:MMA 6-Nylon black do 5 (1:1) l0 MVP:AN do blonde do 5 (I11) l l MMA1AN do blonde do 5 l l 1) 12 VA do blonde do 4 13 St Poly(acrylonitrileblack dry hand, 5

vinyl chloride) no metallic luster Control 1 TiO,Polyvinyl black waxy hand, 2

chloride metallic luster 2 TiO,6-Nylon black do 2 3 TiO,Poly(acrylonitrile chloride) black do 2 Note EVA ethylene-vinyl acetate copolymer St styrene AN acrylonitrile MMA methyl methacrylate VA vinyl acetate Benzene was used as the solvent. lsopropyl alcohol was used as the solvent.

TABLE 2 Pigments Color lndices Blonde Gold 21000 1.00 k 0.50% 64500 0.40 l 1005 0.05 0.30 56200 0.50

What is claimed is:

l. Artificial hair strands consisting essentially of a fiher-forming synthetic thermoplastic polymer, said synthetic thermoplastic polymer containing uniformly dispersed therein and incorporated therewith 0.1 to 10 percent by weight of particles of a cross-linked copolymer of a. at least one radical polymerizable monoethylenically unsaturated monomer selected from the group consisting of styrene, vinyl toluene, methyl vinyl pyridine, methacrylonitrile, acrylonitrile, methacrylic acid, methacrylic acid alkyl esters, acrylic acid, acrylic acid alkyl esters, vinyl acetate and vinyl chloride, and

b. a radical polymerizable dior tri-ethylenically unsaturated cross-linking agent, said cross-linking agent (b) being present in an amount of 0.5 to 30 percent by weight based on the weight of said cross-linked copolymer, said particles being 0.01 to 2 microns in size, said strands having on the surface thereof, along their entire length, a uniformly distributed fine slit-like grooved pattern.

2. The strands of claim 1 wherein the diameter of said strands is within the range of0.08 0.12 mm, said thermoplastic polymer containing 0.5 4 percent by weight of said cross-linked copolymer particles.

3. The artificial hair strands of claim 1 wherein said particles of a cross-linked copolymer are of spheroidal shape.

4. The artificial hair strands of claim 1 wherein said fiber forming synthetic thermoplastic polymer is selected from polyolefins, polyesters, polyamides, polyvinyl chloride, polyacylonitrile, and acrylonitrilewinyl chloride copolymer.

5. The artificial hair strands of claim 1 wherein said radically polymerizable dior tri-ethenically unsaturated cross-linking agent is selected from di-vinyl benzene, di-vinyl toluene, tri-vinyl benzene and di-vinyl sulfone.

6. An artificial hair article in the form of a fall, hair piece or wig comprising a base element to which are attached a multiplicity of bundles of artificial hair strands, said artificial hair strands consisting essentially of a fiber-forming synthetic thermoplastic polymer,

said synthetic thermoplastic polymer containing uniformly dispersed therein and incorporated therewith 0.] to 10 percent by weight of particles of a crosslinked copolymer of a. at least one radical polymerizable monoethyle nically unsaturated monomer selected from the group consisting of styrene, vinyl toluene, methyl vinyl pyridine, methacrylonitrile, acrylonitrile, methacrylic acid, methacrylic acid alkyl esters, acrylic acid, acrylic acid alkyl esters, vinyl acetate and vinyl chloride, and

b. a radical polymerizable dior tri-ethylenically unsaturated cross-linking agent, said cross-linking agent (b) being present in an amount of 0.5 to 30 percent by weight based on the weight of said cross-linked copolymer, said particles being 0.0] to 2 microns in size, said strands having on the surface thereof, along their entire length, a uniformly distributed fine slit-like grooved pattern.

7. The artificial hair article of claim 6 wherein the diameter of said strands is within the range of 0.08 0.12 mm, said thermoplastic polymer containing 0.5 4 percent by weight of said cross-linked copolymer particles.

8. The artificial hair article of claim 6 wherein said particles of a cross-linked copolymer are of spheroidal shape.

9. The artificial hair article of claim 6 wherein said fiber-forming synthetic thermoplastic polymer is selected from polyolefins, polyesters, polyamides, polyvinyl chloride, polyacrylonitrile, and acrylonitrile-vinyl chloride copolymer.

10. The artificial hair article of claim 6 wherein said radically polymerizable dior tri-ethenically unsaturated cross-linking agent is selected from di-vinyl benzene, di-vinyl toluene, tri-vinyl benzene and di-vinyl sulfone.

I! it t 

2. The strands of claim 1 wherein the diameter of said strands is within the range of 0.08 - 0.12 mm, said thermoplastic polymer containing 0.5 - 4 percent by weight of said cross-linked copolymer particles.
 3. The artificial hair strands of claim 1 wherein said particles of a cross-linked copolymer are of spheroidal shape.
 4. The artificial hair strands of claim 1 wherein said fiber forming synthetic thermoplastic polymer is selected from polyolefins, polyesters, polyamides, polyvinyl chloride, polyacylonitrile, and acrylonitrile-vinyl chloride copolymer.
 5. The artificial hair strands of claim 1 wherein said radically polymerizable di- or tri-ethenically unsaturated cross-linking agent is selected from di-vinyl benzene, di-vinyl toluene, tri-vinyl benzene and di-vinyl sulfone.
 6. An artificial hair article in the form of a fall, hair piece or wig comprising a base element to which are attached a multiplicity of bundles of artificial hair strands, said artificial hair strands consisting essentially of a fiber-forming synthetic thermoplastic polymer, said synthetic thermoplastic polymer containing uniformly dispersed therein and incorporated therewith 0.1 to 10 percent by weight of particles of a cross-linked copolymer of a. at least one radical polymerizable monoethylenically unsaturated monomer selected from the group consisting of styrene, vinyl toluene, methyl vinyl pyridine, methacrylonitrIle, acrylonitrile, methacrylic acid, methacrylic acid alkyl esters, acrylic acid, acrylic acid alkyl esters, vinyl acetate and vinyl chloride, and b. a radical polymerizable di- or tri-ethylenically unsaturated cross-linking agent, said cross-linking agent (b) being present in an amount of 0.5 to 30 percent by weight based on the weight of said cross-linked copolymer, said particles being 0.01 to 2 microns in size, said strands having on the surface thereof, along their entire length, a uniformly distributed fine slit-like grooved pattern.
 7. The artificial hair article of claim 6 wherein the diameter of said strands is within the range of 0.08 - 0.12 mm, said thermoplastic polymer containing 0.5 - 4 percent by weight of said cross-linked copolymer particles.
 8. The artificial hair article of claim 6 wherein said particles of a cross-linked copolymer are of spheroidal shape.
 9. The artificial hair article of claim 6 wherein said fiber-forming synthetic thermoplastic polymer is selected from polyolefins, polyesters, polyamides, polyvinyl chloride, polyacrylonitrile, and acrylonitrile-vinyl chloride copolymer.
 10. The artificial hair article of claim 6 wherein said radically polymerizable di- or tri-ethenically unsaturated cross-linking agent is selected from di-vinyl benzene, di-vinyl toluene, tri-vinyl benzene and di-vinyl sulfone. 